work samping case study

8/6/2019 Work Samping Case Study

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The Pennsylvania State UniversityIE 419: Workplace Design, Productivity and Safety

Dr. Andris Freivalds

Case Study 2:Work Sampling

Chris BianchiJaime Mendez

Layan Abdel-Hadi

Wednesday, March 30 th, 2011


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Executive Summary:

This case study is presented using work sampling to show different percentages of

time spent on different activities throughout the day. The work sampling was used for

every group member individually to study their activities over the course of two

weekdays.

First, design-tools was used to get thirty different observations throughout two

days randomly. Every group member gathered data about their days according to the

chosen times, classifying them into nine categories of activities. These activities include

class, eating, gym, homework and studies, leisure, showering, sleeping, socializing and

traveling. The confidence intervals were calculated, put in tables and represented in pie

charts and bar graphs for a clearer interpretation of the numbers obtained.After observing the results, it was noted that Layan spends most her time sleeping

and studying, while Chris and Jaime spend their days mostly sleeping and in class. A few

suggestions were made, according to these results, to help improve the students

schedules.

Introduction:

This case study uses work sampling to compare the daily activities of three

different students by observing their schedules for the days chosen.

Work sampling is a form used to record the data from daily random

observations (Niebel and Freivalds, 2009). This case study uses data recorded by three

different students, over the course of two days of the week, which are Wednesday and

Thursday. The three students, according to what they might be doing during the chosen

days, chose nine categories of activities. These categories include sleeping, eating,

classes, going-to-from classes (traveling), studying and doing homework, sports and

leisure. A percentage of occurrences are found for every activity for every student

individually. By comparing the results, it can be concluded which activities can be cut

back on and which ones the students should do more often.


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Obj ectives:

y Compare and contrast the percentages of different activities between

different group members.y O bserve what percentage of the members days can be used more

efficiently, by increasing or decreasing certain activities.

y The percentages can be used to find the probabilities that we will be doing

a certain event at any given time. This can also be used to find the

allowances in the percentages and a 95% confidence interval.

y R earrange the students schedules of activities.

Methods:

In this case study, the 30 different observations were gathered using design tools.

Every group member individually obtained 30 random times between 0:00 and 24:00 for

each day chosen; Wednesday and Thursday. According to what the students would

possibly be doing during those days, nine activities were chosen and each member used

them to record their specific activities and categorize their time blocks.

Afterwards, every student counted the number of occurrences of every activity for

each day separately, and for both days combined. Those summations were used to find

the percentages of occurrence for every activity each day and for both days combined.

For every day and for the two days combined, a pie chart was created for the percentages

calculated. A bar graph was also created of the combined days for better representation of

the percentages for all three students combined.

By using the percentages, we were able to find the accuracy of each activity using

the equation (l) = sqrt([(3.84)(p)(q)]/n ). The confidence interval was found from

subtracting and adding the accuracy to the probability.


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Results:

All results are calculated from data in the Appendix

Ta b le 1.1: Data for Chris' Number of O bservations per Activity and the Probabilities of O ccurrence

Ta b le 1.2 : Data for Chris' Activity Accuracy (l) and the 95% Confidence Interval for theProbability of O ccurrence

Wednesday Thursday Both

Activity # Observations p # Observations p Total

Observations p class 6 0.2 6 0.2 12 0.2

eating 3 0.1 1 0.033333333 4 0.066666667 gym 2 0.066666667 0 0 2 0.033333333

hw/study 2 0.066666667 4 0.133333333 6 0.1

leisure 5 0.166666667 3 0.1 8 0.133333333 showering 2 0.066666667 1 0.033333333 3 0.05 sleeping 5 0.166666667 10 0.333333333 15 0.25

socializing 3 0.1 3 0.1 6 0.1 traveling 2 0.066666667 2 0.066666667 4 0.066666667

n 30 30 60


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Ta b le 1.3 : Data for Layan's Number of O bservations per Activity and the Probabilities of O ccurrence

Ta b le 1.4: Data for Layan's Activity Accuracy (l) and the 95% Confidence Interval for the Probability of O ccurrence

Wednesday Thursday Both Activity A ccuracy(l) 95% C.I. A ccuracy(l) 95% C.I. A ccuracy(l) 95% C.I.

class 0.143108351 (0.05689,0.34311) 0.143108351 (0.05689,0.34311) 0.101192885 (0.09888,0.30119) eating 0.107331263 (0,0.20733) 0.064218377 (0,0.09756) 0.06310309 (0.00356,0.12977) gym 0.089241246 (0,0.15591) 0 0 0.04540925 (0,0.07875)

hw/study 0.089241246 (0,0.15591) 0.121614144 (0.01171,0.25495) 0.075894664 (0.02411,0.17589) leisure 0.133341666 (0.03333,0.3) 0.107331263 (0,0.20733) 0.086 (0.04733,0.21933)

showering 0.089241246 (0,0.15591) 0.064218377 (0,0.09756) 0.055136195 (0,0.10514) sleeping 0.133341666 (0.03333,0.3) 0.168641632 (0.16468,0.50199) 0.109544512 (0.14046,0.35954)

socializing 0.107331263 (0,0.20733) 0.107331263 (0,0.20733) 0.075894664 (0.02411,0.17589) traveling 0.089241246 (0,0.15591) 0.089241246 (0,0.15591) 0.06310309 (0.00356,0.12977)


Activity #

Observations p #

Observations p Total Observations p class 3 0.1 5 0.166666667 8 0.133333333

eating 1 0.033333333 3 0.1 4 0.066666667 gym 1 0.033333333 0 0 1 0.016666667

hw/study 7 0.233333333 3 0.1 10 0.166666667 leisure 2 0.066666667 1 0.033333333 3 0.05

showering 1 0.033333333 1 0.033333333 2 0.033333333 sleeping 11 0.366666667 14 0.466666667 25 0.416666667

socializing 1 0.033333333 2 0.066666667 3 0.05 traveling 3 0.1 1 0.033333333 4 0.066666667

n 30 30 60



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Ta b le 1.5: Data for Jaime's Number of O bservations per Activity and the Probabilities of O ccurrence

Ta b le 1.6: Data for Jaime's Activity Accuracy (l) and the 95% Confidence Interval for the Probability of O ccurrence

Activity A ccuracy(l) 95% C.I. A ccuracy(l) 95% C.I. A ccuracy(l) 95% C.I. class 0.107331263 (0,0.20733) 0.133341666 (0.03333,0.3) 0.086 (0.04733,0.21933)

eating 0.064218377 (0,0.09756) 0.107331263 (0,0.20733) 0.06310309 (0.00356,0.12977) gym 0.064218377 (0,0.09756) 0 0 0.032386554 (0,0.04905)

hw/study 0.151320117 (0.08201,0.38465) 0.107331263 (0,0.20733) 0.094280904 (0.07239,0.26095) leisure 0.089241246 (0,0.15591) 0.064218377 (0,0.09756) 0.055136195 (0,0.10514)

showering 0.064218377 (0,0.09756) 0.064218377 (0,0.09756) 0.04540925 (0,0.07875) sleeping 0.172407785 (0.19426,0.53907) 0.178487472 (0.28818,0.64515) 0.124721913 (0.29194,0.54139)

socializing 0.064218377 (0,0.09756) 0.089241246 (0,0.15591) 0.055136195 (0,0.10514) traveling 0.107331263 (0,0.20733) 0.064218377 (0,0.09756) 0.06310309 (0.00356,0.12977)


Activity # Observations p #

Observations p Total

Observations p class 5 5/30=.16666 4 4/30=.1333 9 9/60=.15

eating 3 3/30=.1 3 3/30=.1 6 6/60=.1 gym 3 3/30=.1 2 2/30=.0666 5 5/60=.08333

hw/study 4 4/30=.1333 4 4/30=.1333 8 8/60=.1333 leisure 2 2/30=.0666 3 3/30=.1 5 5/60=.09333

showering 1 1/30=.0333 1 1/30=.0333 2 2/60=.0333

sleeping 7 7/30=.2333 10 10/30=.3333 17 17/60=.28333 socializing 1 1/30=.0333 1 1/30=.0333 2 2/60=.0333 traveling 4 4/30=.1333 2 2/30=.0666 6 6/60=.1

n 30 30 60



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The most relevant data is shown on figures below. This is done to get a better comparisonin a more graphical way.

F igure 1: Pie graph for the Chris' percentage of activities on Wednesday

Chr i ' Ob rvat i

19%

10%

7%

7%16%

7%

17 %

10%

7%class

eating

gym

hw/study

leisure

showeringsleeping

social iz ing

traveling

Act ivity A ccuracy(l) 95% C.I. A ccuracy(l) 95% C.I. A ccuracy(l) 95% C.I. class 0.133041347 (.03333,.3) 0.01479 (.01171,.25495) 0.090332718 (.05966,.24033)

eating 0.107238053 (0,.20733) 0.0115 (0,.20733) 0.075894664 (.02410,.17589) gym 0.038729833 (0,.20733) 0.0079 (0,.15591) 0.069282032 (.01341,.15325)

hw/study 0.121614144 (.01171,.25495) 0.01479 (.01171,.25495) 0.085440037 (.04733,.21933) leisure 0.088881944 (0,.15591) 0.0115 (0,.20733) 0.069282032 (.01341,.15325)

showering 0.064031242 (0,.09755) 0.0041 (0,.09755) 0.04472136 (0,.07874) sleeping 0.150996689 (.08201,.38465) 0.0284 (.16467,.50198) 0.113973681 (.16933,.39733)

socializing 0.064031242 (0,.09755) 0.0041 (0,.09755) 0.04472136 (0,.07874) traveling 0.121614144 (.01171,.25495) 0.0079 (0,.15591) 0.075894664 (.02410,.17589)


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F igure 2: Pie graph for the Chris' percentage of activities on Thursday

F igure 3: Pie graph for the Chris' combined percentage of activities for Wednesday andThursday

Ch ri ' hu r ay O erv a ti

20%

3%

0%

13%

10%3%

34%

10%

7%c l s s

ting

gy

h / study

l i sur

s ho ring

s l ping

s o c i l i ing

tr l ing

Ch ri ' Comb i e O bs erv a ti on

20%

7%

3%

10%

13%

%

2

%

10%

7%c l s s

ting

gy

h / study

l i sur

s ho ring

s l ping

s o c i l i ing

tr l ing


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F igure 4: Pie graph for the Layan's percentage of activities for Wednesday

F igure 5: Pie graph for the Layan's percentage of activities for Thursday

Layan's Wednesday Observation10 %

3%

3%

23 %

7%3%

38 %

3%10 % class

eating

gym

hw/study

leisure

showering

sleeping

social iz ing

traveling

Layan's T hu rsday Observation

17 %

10 %

0%

10 %

3%3%

47%

7% 3% class

eating

gym

hw/study

leisure

showering

sleeping

social iz ing

traveling


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F igure 6: Pie graph for the Layan's combined percentage of activities for Wednesday andThursday

F igure 7: Pie graph for the Jaime's percentage of activities for Wednesday

Laya n ' s Comb in e bs erv at ion

13%

7%

2%

17%

5%3%

4 1%

5%7%

c l s s

in

y

h / s

ud y

l i sur

s ho ri n

s l pi n

s o c i l i in

r l in

Ja im e' s e n e sd a y bs erv at ion

17%

10%

10%

13%7%3%

2 4 %

3%

13% c l s s

in

y

h / s

ud y

l i sur

s ho

ri n

s l pi n

s o c i l i in

r l in


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F igure 8: Pie graph for the Jaime's percentage of activities for Thursday

F igure 9: Pie graph for the Jaime's combined percentage of activities for Wednesday andThursday

Ja ime' Thur d ay Obs er at i nc l s s13%

ea t i

10%

gy

7%

hw/ s tud y13 %

le is ur es h o wer i g3%

sl eep i g3 4 %

s o c ia l i i g3%

trave l i g7%

Ja ime' s C m b ined Obs er at i nc la ss16 %

eat i g10 %

gy!

8%

hw/ s tud y13 %leis ure

s h o wer i g3%

sleep i g

29 %

so cia l i " i g3%

trave li g10 %


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F igure 10: Bar graph for the comparison of the combined percentages of activities

between each group number.

Discussion:

After carefully observing the results, and using the accuracy and the percentages

calculated, the confidence interval was found to be 95% for each activity. From the bar

graph above, it can be noted that sleeping occupies most of the time during the day in all

three students schedules. It fills 29% of Jaimes observed days, 41% of Layans, and

25% of Chriss Wednesdays and Thursdays. If the students can decrease their sleeping

hours to 7 hours per one night, then it is possible for them to perform other different

activities from the chosen categories in the gained hours, and increase their number of

occurrences.

Class, doing homework and studying are the second most occurring activities in

the two days of the three students schedules. They consume 29% of Jaimes observed

days, and covers 30% of Chris and Layans observed days.

Comparison of Combined Percentages of Activities Between the Group

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

class eating gym hw/study leisure showering sleeping socializing traveling

Activity

P e r c e n t a g e

ChrisLayanJaime


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The nine categories chosen include class, eating, gym, homework and studies,

leisure, showering, sleeping, socializing and traveling. The category of class includes all

the time consumed in lectures, classes, labs etc. the category of homework and studies

includes the time outside of class spent on all school work, whether it is working on

homework, studying for an exam or quiz, writing papers and case studies, or preparing

for upcoming lectures. Leisure includes any activities performed that are not school

related. For example, checking emails and facebook, reading a book for pleasure or

maybe watching a movie. The category of showering includes all activities done for

grooming purposes, which might include fixing ones hair or getting ready to go to class.

Socializing consists of meeting with other people for purposes that are not related to class

work. For instance, meeting with friends, attending social events or even going to parties.

Traveling covers all the time spent moving from one destination to another, whether ithappens using a car, bus, walking or any other mean of transportation.

The results of this study may vary according to the random timings chosen by

using design tools. For instance, as observed, the observations might skip a big gap

between the specified time limits, which might omit one or more activities during the

day. It could also have a one-minute difference, in which case it would count one activity

twice, and increase its number of occurrences.

C onclusions and Recommendations:

The results of this study show that when randomly observed, the trend betweenthe percentages of activities is similar between different people. Since, there were 30random times per each of the two days that were observed, the study was more accuratethan using only one day per person. However, to improve upon the results, the number of days sampled, number of observations per day, and the number of people observed can beincreased. By doing this, more information can be generated which will increase theaccuracy of the study and provide more possible conclusions to be drawn. For instance,if the number of people sampled were increased, trends between gender, age, andethnicity would be more applicable. If the number of days sampled were increased,trends could be drawn between how the day of the week effects people's activity

percentages. A specific difference would most likely be correlated between activities performed during the weekend versus the weekdays. The number of activities in which a person could be doing could be increased to add a more specific analysis of the testsubjects being studied.

Sampling people during different seasons could also change the results and provide information to how weather may affect their activities. O ccupations can also


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effect people's activities. For example, a student will most likely have a much differentschedule and set of activities than a full-time employee. Marital status, having a family,or living alone may also effect one's activities. The location in which a person livescould also impact the study. For example, someone living in the city versus a rural areawill most likely have much different lifestyles.

There are many different variables that can be studied in order to form certaincorrelations between different people and the activities in which they partake.R egardless, the most necessary improvements for this work sampling study would be toincrease the number of days observed, the number of observations, and the number of

people observed.

Wednesday Thursday #

b s. Time A ctivity Time A ctivity 1 0:43 leisure 1:03 leisure 2 0:46 leisure 1:04 leisure 3 1:27 leisure 1:16 leisure 4 4:11 sleeping 2:20 sleeping 5 6:40 sleeping 3:06 sleeping 6 6:48 sleeping 3:54 sleeping

7 7:39 sleeping 5:09 sleeping 8 7:51 sleeping 5:13 sleeping 9 8:04 showering 5:15 sleeping

10 9:00 tr a $ eling 6:11 sleeping 11 9:08 class 6:26 sleeping 12 9:53 class 7:29 sleeping 13 9:59 leisure 8:43 sleeping


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App endix:

Ta b le2.1: Datafor R andomSamplingof Chris'sWednesd

ay andThursdayActivities

14 10:13 class 9:18 showering 15 11:50 eating 9:34 eating 16 11:53 eating 10:58 class 17 12:13 tr a % eling 11:00 class 18 12:27 class 11:06 tr a % eling 19 13:54 leisure 14:10 tr a % eling 20 14:34 class 14:39 class 21 15:23 class 14:42 class 22 15:42 eating 14:49 class 23 16:11 gym 15:03 class 24 16:52 gym 19:22 hw/study 25 17:17 showering 19:45 hw/study 26 18:15 hw/study 20:02 hw/study 27 18:25 hw/study 20:05 hw/study 28 20:28 soci alizing 20:50 soci alizing 29 21:36 soci alizing 20:55 soci alizing 30 23:08 soci alizing 23:04 soci alizing


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Ta b le 2.2: Data for R

andom Sampling of Layan's Wednesday and Thursday Activities

Wednesday Thursday & b s. Time A ctivity Time A ctivity

1 1:21 sleeping 0:44 sleeping 2 1:56 sleeping 1:20 sleeping 3 4:59 sleeping 1:27 sleeping 4 5:26 sleeping 2:21 sleeping 5 5:51 sleeping 2:45 sleeping

6 6:16 sleeping 3:36 sleeping 7 6:41 sleeping 3:45 sleeping 8 6:42 sleeping 4:59 sleeping 9 6:57 sleeping 5:03 sleeping

10 7:06 sleeping 6:06 sleeping 11 8:58 tr a ' eling 6:10 sleeping 12 9:56 class 7:08 sleeping 13 12:04 hw/study 7:56 sleeping 14 12:36 hw/study 7:57 sleeping 15 13:28 hw/study 8:29 showering

16 13:48 hw/study 9:39 eating17 13:55 leisure 11:35 class18 14:08 leisure 11:45 class19 14:13 tr a ' eling 12:09 eating20 14:57 class 12:44 eating21 15:04 class 12:53 tr a ' eling 22 15:31 tr a ' eling 14:08 class


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Ta b le 2.3: Data for R andom Sampling of Jaime's Wednesday and Thursday Activities

23 17:07 gym 14:09 class24 18:36 tr a ( eling 14:18 leisure 25 19:11 showering 15:14 class26 19:33 tr a ( eling 16:10 hw/study 27 20:02 eating 16:18 hw/study 28 22:00 hw/study 18:49 hw/study 29 22:46 soci alizing 19:52 soci alizing30 24:00:00 sleeping 20:57 soci alizing


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Wednesday Thursday

)

b s. Time A ctivity Time A ctivity 1 1:09 sleeping 1:21 sleeping 2 1:32 sleeping 1:56 sleeping

3 2:30 sleeping 4:59 sleeping 4 2:52 sleeping 5:26 sleeping 5 2:55 sleeping 5:51 sleeping 6 3:36 sleeping 6:16 sleeping 7 3:53 sleeping 6:41 sleeping 8 7:49 eating 6:42 sleeping 9 8:33 showering 6:57 sleeping

10 8:53 tr a 0 eling 7:06 showering 11 9:06 class 8:58 class 12 10:01 class 9:56 soci alizing

13 10:21 class 12:04 hw/study 14 10:23 class 12:36 hw/study 15 11:28 soci alizing 13:28 eating 16 11:45 eating 13:48 eating 17 11:52 tr a 0 eling 13:55 leisure 18 11:56 tr a 0 eling 14:08 tr a 0 eling 19 12:05 class 14:13 tr a 0 eling 20 13:28 tr a 0 eling 14:57 class 21 14:02 gym 15:04 class 22 15:14 gym 15:31 class

23 15:47 gym 17:07 gym 24 17:55 hw/study 18:36 gym 25 17:57 hw/study 19:11 hw/study 26 19:02 hw/study 19:33 hw/study 27 21:41 eating 20:02 eating 28 22:58 hw/study 22:00 leisure 29 23:11 leisure 22:46 leisure 30 23:39 leisure 24:00:00 sleeping

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